In a photoresist process which is one of semiconductor manufacturing processes, a surface of a semiconductor wafer (hereinafter, referred to as “wafer”) is coated with resist, the resist is exposed to light via a preset pattern and developed so as to form a resist pattern. Generally, such a process is performed by a system in which a coating and developing apparatus that coats and develops resist is connected with an exposure apparatus. In a conventional developing process for photoresist (hereinafter, referred to as “resist”) by a developing module provided in the coating and developing apparatus, a developing solution is supplied through a nozzle onto a surface of a wafer that has been coated with resist and exposed to light via a preset pattern. To obtain process uniformity in a wafer surface, the developing solution is supplied such that a liquid film is uniformly formed on the entire surface of the wafer, and the resist is dissolved by the liquid film.
To form the liquid film of the developing solution, there is known a method (puddle type developing process) for accumulating liquid on the entire surface of the wafer by discharging the developing solution onto the stationary wafer while moving a nozzle having an elongated discharge port, or there is known a method (puddless type developing process) for supplying the developing solution in, e.g., a diametric direction of the wafer while rotating the wafer around a vertical axis and coating the developing solution on the wafer by a centrifugal force.
In consideration of the composition of materials of the resist, a reaction between the developing solution and the resist may progress for a relatively short time. In the aforementioned methods, however, a great amount of developing solution has been used to form a uniform liquid film, and a great amount of time has been taken to supply the developing solution onto the wafer. Since the process of supplying the developing solution is so time-consuming, a certain amount of time, e.g., about 30 seconds to about 60 seconds has been required till the reaction between the developing solution and the resist is completed after the supply of the developing solution is begun.
Meanwhile, a liquid immersion exposure process may be performed as an exposure process for a wafer. To suppress an influence of a liquid used in this liquid immersion exposure process upon the wafer, a high water-repellent resist tends to be used. If the high water-repellent resist is used, however, some portions on the resist may not be wet with the developing solution when the resist is developed by the aforementioned methods. Further, a diameter of the wafer tends to increase, and as the diameter of the wafer increases, there is an increasing tendency for the areas not to be wet with the developing solution on the surface of the high water-repellent resist. Accordingly, to form a uniform liquid film of the developing solution for the high water-repellent resist, a greater amount of developing solution may be required, which may cause increase of processing cost and supply time for the developing solution. As a result, high throughput of a coating and developing apparatus may not be achieved.
Thus, the present inventors have considered supplying mist of the developing solution to the wafer to form the liquid film on the entire surface of the wafer. Meanwhile, in a conventional developing apparatus, a mechanism for supplying a developing solution through a nozzle and a cleaning mechanism for cleaning a wafer are installed in the same apparatus. This cleaning mechanism supplies a cleaning solution to the wafer on which the liquid film of the developing solution is formed and performs a cleaning process on the wafer.
Even in the above-described developing apparatus which supplies mist of the developing solution to the wafer, the developing mechanism for supplying the mist of the developing solution and the cleaning mechanism can be installed in the same apparatus in the same manner as the conventional developing apparatus. However, with this configuration, while the mist of the developing solution is supplied to the wafer and while the liquid film of the developing solution and the resist react with each other, the cleaning mechanism cannot perform a cleaning process to the wafer and should stop the process and wait to resume. On the contrary, while the cleaning mechanism is performing a cleaning process, the mechanism for supplying the mist of the developing solution cannot perform a process to the wafer and should stop the process and wait to resume. As a result, sufficient improvement in throughput may not be achieved.
In Patent Document 1, it is disclosed that mist of a developing solution is supplied into a chamber accommodating a substrate therein. However, the substrate is temperature-controlled by being heated on a hot plate, and, thus, an evaporation amount of the developing solution become increased, which may cause an increase in processing costs.    Patent Document 1: Japanese Patent Laid-open Publication No. 2005-277268 (paragraphs [0139], [0141] and [0178])